The present disclosure relates to a method for operating a plurality of electrochemical cells and also to a cell assembly having a plurality of electrochemical cells. In particular, the present disclosure relates to improvements in the case of the switch-mode connection of individual cells so as to control a terminal voltage in a cell assembly.
Electrochemical storage cells are frequently connected in parallel circuits and/or in series circuits to cell modules so as to provide predefined electrical parameters. During the operation of the cells, care is to be taken that the cells are used in a uniform manner and in accordance with their state of charge and aging state so as to output electrical energy. In particular, in the case of increasing electrification of personal individual transport by means of electrically driven vehicles, there is a demand for long lasting and reliable cell modules. By way of example, a method is known for regulating the amount of energy that is output, wherein the battery voltage is set in a regulated manner using a PWM signal as a control signal that is transmitted to the individual cells. The PWM-command from a microcontroller or another logic unit is relayed at each cell to a power electronics system that connects the cells into the entire string using a predetermined clock signal (“duty cycle”) or bridges said cells. In the case of this method, it is disadvantageous that all the cells are simultaneously connected or disconnected so that the total battery voltage is varied between its possible maximum value and 0. The resulting fluctuations of the output voltage render an accordingly large and cost-intensive choke necessary for the smoothing process. It is therefore an object of the present disclosure to eliminate the abovementioned disadvantages of the prior art.